Recently, as the lack of an energy resource such as petroleum or coal is expected, the interest in the substitute energy has been more increased. In this regard, a solar cell converting solar energy into electrical energy is spotlighted.
A solar cell (or photovoltaic cell) is a core element in solar power generation to directly convert solar light into electricity.
For example, if the solar light having energy greater than band-gap energy of a semi-conductor is incident into a solar cell having the PN junction structure of a semi-conductor, electron-hole pairs are generated. As electrons and holes are collected into an N layer and a P layer, respectively, due to the electric field formed in a PN junction part, photovoltage is generated between the N and P layers. In this case, if a load is connected to electrodes provided at both ends of the solar cell, current flows through the solar cell.
The current generated from the solar cell is connected to a junction box through a bus bar. In general, in order to connect the bus bar formed on the top surface of a solar cell panel to the junction box, holes having positive and negative polarities are formed in a solar cell substrate. In order to form the holes, an additional process is required for the substrate, and the number of the processes may be increased. In addition, the solar cell substrate may be damaged due to the cracks between the holes.